[llvm] [LV] Vectorize FMax w/o fast-math flags. (PR #146711)

[Ramkumar Ramachandra via llvm-commits]

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@@ -939,10 +940,15 @@ RecurrenceDescriptor::InstDesc RecurrenceDescriptor::isRecurrenceInstr(
                   m_Intrinsic<Intrinsic::minimumnum>(m_Value(), m_Value())) ||
             match(I, m_Intrinsic<Intrinsic::maximumnum>(m_Value(), m_Value()));
     };
-    if (isIntMinMaxRecurrenceKind(Kind) ||
-        (HasRequiredFMF() && isFPMinMaxRecurrenceKind(Kind)))
+    if (isIntMinMaxRecurrenceKind(Kind))
       return isMinMaxPattern(I, Kind, Prev);
-    else if (isFMulAddIntrinsic(I))
+    if (isFPMinMaxRecurrenceKind(Kind)) {
+      if (HasRequiredFMF())
+        return isMinMaxPattern(I, Kind, Prev);
+      if ((Kind == RecurKind::FMax || Kind == RecurKind::FMaxNoFMFs) &&
+          isMinMaxPattern(I, Kind, Prev).isRecurrence())
+        return InstDesc(I, RecurKind::FMaxNoFMFs);
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artagnon wrote:

Doesn't this effectively remove the need for FMax? Can FMaxNoFMFs be folded into FMax? Ultimately, can we strip the hasRequiredFMFs() check once there are follow-ups handling No-FMFs for all the patterns?

https://github.com/llvm/llvm-project/pull/146711